This invention relates generally to traction systems and more particularly to a traction apparatus that is capable of applying traction forces simultaneously to selected areas of the human spine for the purpose of remodeling spinal posture toward an ideal normal static spinal model.
The ideal normal static spinal model can be characterized by two main criteria. The first of these criteria requires vertical alignment of all of the vertebral centers of mass over the lower limb centers of mass. This means that the skull center of mass, the thoracic center of mass, the pelvic center of mass, the mid-knee, and the mid-ankle are all vertically aligned in both the frontal and median planes. The second of these criteria requires that the primary (kyphotic) and secondary (lordotic) spinal curvatures, as viewed in the median plane, subtend a circular arc of sixty-three degrees.
Abnormal human spinal postures can be categorized as translations and/or rotations of the skull, thorax, or pelvis relative to the immediately inferior center of mass in a 3-dimensional Cartesian coordinate system. Abnormal postures defined in this manner would therefore consist of positive/negative translations along the x, y, z axes or positive/negative rotations about these axes. An abnormal posture could be as simple as a single deviation along or about one axis for one center of mass or as complex as to involve six degrees of freedom for each center of mass relative to the one below.
Spinal degenerative disease, particularly disc disease, is always promoted and often initiated by the alteration of spinal posture from the ideal. As postural alignment departs from the ideal, the transmission of force through the spine is altered, and damaging forces are applied into localized regions of the spine. These areas gradually deteriorate and decline in function and integrity. The resultant spinal instability leads to symptoms and disability. Therefore, any method and apparatus that can effectively correct spinal postural abnormalities is of great benefit to mankind.
The known application of traction forces to the human spine dates back to the time of Hippocrates. However, the greatest portion of study and development in this field has been completed within the last fifty years. With few exceptions, spinal traction has consisted of axially applied forces, most often to address such clinical entities as fracture, dislocation, radicular pain, or spondylosis.
It is only recently that a field of study has developed that entails the use of traction forces with the express purpose of remodeling spinal posture. To date, the most effective postural remodeling efforts are based on known rheologic principles and soft tissue deformation concepts. In practice, these principles dictate repetitive application of forces at sufficient amplitude, specific angle of incidence, and for sufficient time periods to exhaust elastic resistance and achieve the desired plastic deformation of the soft tissue elements being tractioned. The present invention allows the repetitive application of such controlled forces in the cervical, thoracic, and lumbar spine, as well as within the shoulder girdles and rib cage.
The use of traction for the purpose of correcting abnormal spinal postures has a limited history. The earliest attempts were efforts to correct scoliotic spinal curvatures. One such invention, known as the Von Lackum table, involved placing the subject flat on a table and applying forces to the subject by way of belts strapped around the torso and secured to either side of the table under tension.
Recent renewed interest in postural remodeling, particularly within the field of chiropractic, has led to advancement in this field. However, even though the basic principles of spinal postural remodeling are now clearly defined, the actual application has been limited and concentrated almost exclusively upon the cervical spinal lordotic posture. Exemplary of the prior art devices directed toward remodeling spinal posture are those described in U.S. Pat. Nos. 4,951,654 and 5,129,881. However, in these references, only passive forces of low amplitude, with little control over angle of incidence are applied below the cervical spine. The traction devices of the prior art are therefore limited in their ability to achieve spinal postural remodeling below the level of the cervical spine. In addition, both of these references produce an undesirable component of basilar compression at the antlanto-occipital region.
In U.S. Pat. No. 4,951,654 to Gambale et al., a subject reclines over an angled recumbent table with a harness placed across the forehead to exert a controlled compressive extension force to the cervical spine. No active forces are applied below the level of the forehead. Passive gravitational force is recruited by placing a fulcrum under the lower back.
In U.S. Pat. No. 5,129,881 to Pope, a subject is seated in a chair with lumbar and dorsal support. A harness is passed around the cervical spine from the front and anchored in front of the subject at a controlled angle and force. A second harness is applied to the forehead and around the lower back skull and placed under tension to exert an extension force to the cervical spine at a controlled angle and force. A fulcrum is applied between the chair and the subject at the lumbar spine, but no active force is applied below the cervical spine.
Other prior art methods of cervical traction with the intent of spinal postural remodeling include having the subject lie supine on a flat bench with a small fulcrum under the cervical spine and a harness attached to the chin and/or forehead to exert a force superiorly and/or posteriorly relative to the torso. Alternatively, the subject may be seated with the head tipped back and with a harness across the forehead attached to a weight pulling the head downward into forced extension.
Still other prior art methods of applying forces into the dorsolumbar spine for the purpose of spinal postural remodeling include exercises that are done in a supine posture while lying over a fulcrum at the mid-dorsal spine, or lying over a sling that is suspended from above, with the sling placement at the area of the dorsolumbar spine to be tractioned.
It is therefore a principal object of the present invention to provide a traction apparatus in which the subject to be tractioned is placed in a semi-upright posture that allows complete and easy access to the spine and axial skeleton from any direction for unrestricted traction setup. This position is nearly identical to the subject's natural upright standing posture from the pelvis up, thereby maintaining active proprioceptive input to the nervous system during traction application to thereby facilitate postural remodeling. This position is also the same as the one in which the ideal normal static spinal model is drawn, thereby allowing visual confirmation of correct traction positioning by simple comparison of the actual setup to the ideal.
It is a further object of the present invention to provide a traction apparatus that permits the application of traction forces, controllable both with respect to amplitude and angle of incidence, to be actively and directly applied to the pelvis, the dorsolumbar spine, each shoulder girdle, the cervical spine, and the head.
It is a further object of the present invention to provide a traction apparatus that provides extreme variability in the angle of incidence of traction forces. A cervical fulcrum can originate in any position within the median plane from in front of and below the subject to directly above the subject. A head halter can originate in any position within the median plane from below and behind the subject to above and in front of the subject. A pelvic traction belt, dorsolumbar traction belt, and shoulder harness can originate from below to above the point of subject contact within the median plane. In addition, by placing a block underneath one knee at the knee rest, rotation of the pelvis about the z-axis can be achieved, with compensatory z-axis rotational changes taking place throughout the spine. In the same manner, by placing wedges unilaterally within the traction belts, between the subject and the pelvic rest, or by applying asymmetrical tension to the shoulder harness, the subject can be rotated about the y-axis, thereby introducing a rotational component to the angle of incidence.
It is a further object of the present invention to provide a traction apparatus that includes a shoulder harness for providing a more stable base for cervical traction application. The shoulder harness allows placement of the shoulders in a retracted position to achieve more effective postural remodeling of the cervical spine, which anatomically extends to the second dorsal vertebra. In addition, forces can be directed into the thoracic spine and rib cage by using the shoulders as levers. Finally, traction forces can be directed into the shoulders themselves to address abnormal shoulder postures.
It is a further object of the present invention to provide a method of alleviating the basilar compression component at the atlanto-occipital region during cervical extension traction.
It is yet another object of the present invention to provide a traction apparatus that is capable of applying postural corrective traction forces to all areas of the spine, axial skeleton, and shoulder girdles at the same time. The concerted application of traction forces throughout the spine increases the effect of each local application by creating a corrected point of reference for local applications and by increasing the amplitude of the neurologic proprioceptive input that facilitates more rapid postural remodeling.
These and other incidental objects are accomplished in accordance with the illustrated preferred embodiment of the present invention by providing a traction apparatus including a frame, knee and pelvic rests within the frame for receiving the subject, a head halter, a cervical fulcrum, an occipital sling, a shoulder harness, a dorsolumbar traction belt, a pelvic traction belt, and associated tensioning devices operative for applying desired tractional forces to the spine and other anatomic contact points of the subject.